This invention relates to rotary connections and apparatus to disconnect and reconnect such rotary connections. In particular, the invention relates to apparatus for remotely disconnecting and for manually reconnecting a rotary drive shaft, such as those used to drive accessories powered by an engine.
In various applications, a powered device such as a generator is driven by a drive shaft from an engine. In many cases, failure of such a powered device can be detected in time to avoid significant damage to the device if the device is disconnected. Similarly, a large accessory can cause damage to an engine, should the large accessory seize during the operation of the engine. In such cases, the provision of a disconnect device is cost-justified.
In aircraft, generator systems are provided with redundancy of operation, either by providing battery power in the case of single engine aircraft or, in the case of multi-engine aircraft, by providing multiple generators which provide a significant margin of safety. In certain aircraft such as those used in electronic and weather information gathering, it may be desired to fly the aircraft for extended periods of time. If, for example, a generator on the aircraft fails, the aircraft may have more than ample power to continue on its mission with more available electric power than would be necessary to meet any safety requirements for the aircraft. In such cases, a failed generator driven by one of the main engines of the aircraft may be disconnected, allowing the engine in the aircraft to continue without the interference of the generator. In the prior art, this disconnect feature had either been unavailable or had been effected by a frangible member. While such frangible members are expensive, they tend to be economical when compared to the expense of repairing other equipment which may be damaged or even when compared to the expense of prematurely aborting a mission.
In many cases, a warning of a imminent failure may be caused by non-failure-related events, such as a transient overload or a false signal. In the event that the generator or other accessory may be safely eliminated for the duration of a flight, a pilot may choose to disconnect the accessory for purely economic reasons, provided that the disconnection itself does not involve costly replacements. Furthermore, there may be other cases in which it may be desired to give the pilot an ability to elect to continue operation of a generator or other accessory, even with a failed part, because the needs of a particular operation outweigh the economic considerations.
For these reasons, it is desired to provide a disconnect device which may be selectively or automatically operated remotely. It is further desired that a disconnect device be provided in which the disconnect device can be reused by merely resetting the disconnect device. It is further desired that a means be provided to disconnect a device driven by a rotary shaft in which divers and remote signals can be used to effect disconnection. It is further desired that such a remotely operated disconnect device be able to be used in order to facilitate economical disconnection of the driven device.
It is further desired to provide a resettable disconnect device which must be actively reset by a mechanic in order that the mechanic cannot overlook the occurrence of a malfunction of the driven device. It is further desired that equipment, such as an aircraft engine powering such a driven device be able to be properly operated without the use of such a driven device until such time as repairs can be conveniently effected.
It is a further object of the invention to provide such a disconnect device for a rotating drive system in which one of the members, such as the driven member, can be braked after disconnection.